Trapped particle heat transfer tube

Abstract

An arrangement for a heat exchange surface in a boiling application that retains particulate material between fins to provide nucleate boiling sites. The heat exchange surface most typically is part of a heat exchange tube and retains the particulate material by transversely extending the tops of the fins. The fins and extended tops form channels with a restricted opening at the top of the channel that prevents passage of the particulate material out of the channel. The surface may be formed on the inside or outside of tubes.

What is claimed is: 
     
       1. A thin walled heat transfer body comprising: a heat transfer surface defined by one side of a thin walled conductive body;   a plurality of parallel fins fixed to said heat transfer surface;   a plurality of channels defined by and extending between said fins; and   particulate material located in and retained in said channels by said fins.   
     
     
       2. The apparatus of claim 1 wherein the outer end of said fins extend over said channel to retain said particulate material. 
     
     
       3. The apparatus of claim 2 wherein said outer ends of said fins form slots that extend parallel to said fins. 
     
     
       4. The apparatus of claim 3 wherein said slots are continuous. 
     
     
       5. The apparatus of claim 1 wherein said fins are integrally formed from the material of said body and said particulate material has the same composition as said fins and said body. 
     
     
       6. The apparatus of claim 5 wherein the material of said body, fins and particulate material is copper. 
     
     
       7. The apparatus of claim 1 wherein said particulate material has approximately the same width as said channels. 
     
     
       8. A heat transfer tube comprising: a heat transfer surface defined by a side wall of said tube;   a plurality of parallel fins fixed to the side wall of said tube;   a plurality of channels defined by and extending between adjacent fins; and   particulate material located in and retained in said channels by said fins.   
     
     
       9. The tube of claim 8 wherein the outer end of said fins extend over said channel to retain said particulate material. 
     
     
       10. The tube of claim 9 wherein said outer ends of said fins form slots that extend parallel to said fins. 
     
     
       11. The tube of claim 10 wherein said slots are continuous. 
     
     
       12. The tube of claim 8 wherein said fins are integrally formed from a base metal of said tube and said particulate material has the same composition as said fins and said tube. 
     
     
       13. The tube of claim 8 wherein said particulate material has approximately the same width as said channels. 
     
     
       14. The tube of claim 8 wherein said fins and particulate material are located on the outside diameter of said tube. 
     
     
       15. The tube of claim 8 wherein said fins extend circumferentially around said tube. 
     
     
       16. The tube of claim 8 wherein said fins and particulate material are located on the inside diameter of said tube. 
     
     
       17. A heat transfer tube for boiling liquids comprising: a heat transfer surface defined by a side wall of said tube;   a plurality of parallel fins formed on the side wall and said fins having a top portion that extends transversely;   a plurality of channels defined by and extending between adjacent fins;   a restricted opening at the top of said chamber defined by the tops of said fins; and,   particulate material located in said chamber and having a size that prevents passage of said particulate material through said restricted opening.   
     
     
       18. The tube of claim 17 wherein said outer ends of said fins form slots that extend parallel to said fins. 
     
     
       19. The tube of claim 17 wherein said particulate material has the same composition as said tube. 
     
     
       20. The tube of claim 17 wherein said particulate material has approximately the same width as said channels. 
     
     
       21. The tube of claim 17 wherein said fins extend circumferentially around said tube.